What is Split Air Conditioner? Differences & Advantages


Split air conditioners are commonly used in residential air conditioning. What is a split air conditioner and what are the differences and advantages it has over the others?

Split air conditioner is a direct expansion air conditioning system that consists of an evaporator and a condenser that is installed indoor and outdoor respectively and separately. The evaporator and the condenser are connected by thermally insulated copper pipes filled with refrigerant to transfer the heat from indoor to outdoor.

The evaporator and the condenser of the split air conditioner are sometimes called as the indoor unit and the outdoor unit respectively because it is relatable to their installed location. The working principle of the split air conditioner is relatively simple but packed with advantages.

How Split Air Conditioner Works?

The split air conditioner uses the evaporator to absorb the heat in a room, transfer the heat via the refrigerant to the condenser and the condenser release the heat to the surrounding. Through this process, the split air conditioner provides cooling to the room.

A compressor can be found inside the condenser of the split air conditioner. The compressor compresses the gas refrigerant and thus, increases its pressure and temperature before the refrigerant enters the condenser coil. The fan of the condenser draws in the surrounding air and circulates it through the condenser coil and thus, changes the refrigerant from gas to liquid form.

The liquid refrigerant travels to the evaporator and changes from liquid back to gas form by the expansion valve located inside the evaporator. The expansion of the refrigerant causes its pressure and temperature to drop rapidly before the refrigerant enters the evaporator coil. The fan of the evaporator draws in air and circulates it through the evaporator coil and therefore, provides cooling to the room.

The evaporator of the split air conditioner removes a certain amount of moisture in the air during its operation. Air condenses when in contact with the cold evaporator coil and changed from water vapor to liquid water. This liquid water is often called condensate water. Then, the condensate water is discharged from the evaporator via a drain pipe.

The split air conditioner has a filter at the evaporator, but not at the condenser, to reduce the dust that goes into the evaporator coil and fan. Besides, a remote controller is usually used rather than a wired controller to turn on/off, set the temperature, fan speed, timer, and other settings of the split air conditioner.

Split Air Conditioner vs Central Air Conditioner

A house installed with split air conditioners has one evaporator in every room and multiple condensers at the outside of the house. Meanwhile, a house installed with a central air conditioner may have one or two supply air diffusers in every room, one evaporator above the ceiling, and one condenser at the outside of the house.

While the split air conditioner always has one evaporator and one condenser, the central air conditioner can have either one evaporator with multiple supply air diffusers or multiple evaporators. Nevertheless, most central air conditioners have only one condenser.

Most split air conditioners are air-cooled while most central air conditioners are water-cooled. Central air conditioners usually have much more cooling power than split air conditioners.

Some other differences between the split air conditioner and the central air conditioner are as follow:

Comparison MetricsSplit Air ConditionerCentral Air Conditioner
Cost of purchaseCheaperMore expensive
Cost of installationCheaperMore expensive
Cost of maintenanceCheaperUsually more expensive
Ease of maintenanceEasyModerate to difficult
Energy efficiencyGoodBetter
Available cooling capacityMostly up to 24,000 BTU per unitMore than 240,000 BTU per unit
House exterior aestheticPoor due to many condensersGreat because of one condenser only
ApplicationApartment, landed house, small officeLarge house, shopping mall, hotel

Advantages of Split Air Conditioner

  • Low cost – Split air conditioners are cheaper to purchase, install and maintain due to their simple yet effective design.
  • Easy to maintain – Split air conditioners have a simple design that enables non-professional users to service the air conditioners by themselves. Read about: How to Service Air Conditioner Yourself? (How I Did It)
  • Reliable – Split air conditioners are individually installed in every room and thus, one unit breakdown doesn’t affect the other units, unlike central air conditioners where the breakdown of a condenser unit will stop the operation of all connected evaporators.
  • Faster installation – Split air conditioners required fewer pipes and cables compared to other air conditioning systems and thus, enable significantly quicker installation.
  • Good energy efficiency – Split air conditioner with inverter may offer better energy efficiency than some central air conditioners, especially when the installation of the central air conditioner is poor which has a high chance to happen due to the complexity of the central air conditioner.

What is Inverter in Split Air Conditioner?

Inverter is an air conditioning technology that enables the control of the speed of the compressor. The cooling power of the split air conditioner can be increased or decreased by adjusting the speed of its compressor. A split air conditioner with an inverter is able to maintain a more precise room temperature. Besides, it has a better energy efficiency compared to a split air conditioner without an inverter.

The inverter technology in split air conditioners also extended to most of the other air conditioning systems such as the multi split and the VRF (variable refrigerant flow). An inverter split air conditioner is often 20% more expensive than a non-inverter one.

Find out: Buying Air Conditioners: Is Inverter AC Worth the Price?

Yu Chang Zhen

Yu was working in the air conditioning industry for the past 7 years, covering from design to installation and maintenance. Yu wish to share all the things he learned with the people around the world.

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